The subject matter of the present disclosure relates to the field of cellular fixed networks and, more specifically, to providing improved bandwidth utilization over a Universal Mobile Telecommunication System (UMTS) terrestrial radio access network (UTRAN).
The rapid evolution of video communication over wireless communication networks for mobile communications, such as but not limited to, 3G networks, etc. creates a demand for increasing bandwidth of the cellular networks. The demand for increasing the bandwidth of the cellular network pushes more and more cellular network operators to adapt a UMTS network architecture. The UMTS network architecture enables network operators to enjoy the improved cost-efficiency of UMTS while protecting their 2G investments.
The UMTS architecture includes a new radio access network, UMTS terrestrial radio access network (UTRAN) that interfaces between a plurality of mobile terminals (MT) and a core network of a cellular operator. A common UTRAN can comprise one or more radio network controllers (RNC). Each RNC can be connected to a plurality of nodes (i.e. node B). Each node B connects with a plurality of MTs via a radio interface.
The interface between the UTRAN and the GSM Phase 2+ core network (CN) is called Iu (the interface between an RNC and a CN). The Iu is divided into two types of interfaces. The first type is the interface between the RNC and the packet-switched domain of the CN and is called Iu-PS. The Iu-PS is used for packet-switched data. The second type is the interface between the RNC and the circuit-switched domain of the CN and is called Iu-CS. The Iu-CS is used for circuit-switched data. The interface between the RNC and a node B is referred as Iub and the interface between an RNC and another RNC is referred as Iur. The Iu, Iub, and Iur interfaces can be used over a connection using ATM transmission protocol. More information about UMTS is disclosed in UMTS release 1 (Rel. '99), the content of which is incorporated herein by reference.
In the Iub interface, between an RNC and a node B, the data is organized in Iub blocks. A common Iub block starts with an Iub header, which is followed by the data and is typically terminated with two bytes of Iub Cyclic Redundancy Check (CRC). The length of an Iub block can be varied and may depend on the type of session to which it belongs (audio session, video conferencing session, data session, etc.). For example, consider an Iub block that carries video conferencing data, which is multiplexed according to the H.223 protocol. The data may be organized in one or more H.223 protocol data units (PDU). Each PDU starts with a header and can be followed by a flag.
A PDU can carry a single type of content (control or audio or video, for example) or a mix of types of content, audio data followed by video data or video data followed by audio data, for example. The content type of a PDU is defined by a multiplexing code (MC). The MC is a field in the header of the PDU. The MC defines an entry in a multiplex table. The multiplexing table can be sent within the control information that is sent while establishing the connection with the moving terminal. Each entry in the multiplexing table defines the type of the content that is carried by the PDU. Usually, when MC is zero, the PDU carries signaling and control information. Other values of MC can be used to mark PDUs that carry audio data, another MC may define PDUs that carry video data, another MC may define PDUs that carry video data followed by audio data, and alternatively another MC may define PDUs that carry audio data followed by video data.
The packaging format of an Iub block includes an overhead of a plurality of bytes that are used as flags, headers, CRC, etc. Some of this overhead is needed for other sections of the connection, for example for the air interface between an MT and a node B and may not be needed over a terrestrial connection.
Therefore, there is a need for a system and method for reducing the overhead bytes in the Iub blocks. The system can remove some of the flags, headers, etc. Such a system can improve bandwidth utilization over the communication line between an RNC and the plurality of node Bs.
Furthermore, from time to time there is a need to give priorities to certain types of communication over other types to provide a desired quality of service (QoS). For example, in case that a connection between a node B and an RNC is overloaded, then video data can be removed from the connection releasing bandwidth for carrying audio session data. Therefore, there is a need for a system that can distinguish between video data and audio data that is carried by an Iub and that is capable of removing the video data in order to release bandwidth or reduce bandwidth consumption.